For many years, valve assemblies have used a rigid valve plate which is loosely coupled to the stem of an actuator for supporting a resilient valve member or seat. The valve assembly might be moved against an outlet opening of the valve by a spring and when the actuator is energized, the valve assembly is lifted to open the valve. Such a valve assembly is intended to be loosely connected to the stem of the valve actuator to allow it to toggle about the actuator stem to compensate for misalignment of the valve assembly and valve seat. At the same time, the resilient valve member is made to slip on the valve plate in an easy assembling manner to reduce the cost of manufacture.
Such prior art valve designs are susceptible of distortion of the resilient valve member should the gas pressure on the inlet side above the valve assembly become excessive. Gas passing through the loose coupling around the hole in the valve plate to the underside of the resilient valve member distorts the valve member and possibly blooms the valve member through the valve outlet opening.
The present invention is concerned with the addition of a backup or sealing member adjacent the rigid valve plate and inside the resilient valve member to prevent the excessive gas pressure from distorting the resilient valve member.